Conventionally, Patent Document 1 discloses a control apparatus for an internal combustion engine which is provided with an in-cylinder pressure sensor disposed in each cylinder and calculating means for calculating heat production for every unit crank angle per each cylinder during combustion stroke based upon a pressure signal from each in-cylinder pressure sensor. In this control apparatus for the internal combustion engine, a fuel supply quantity (air-fuel ratio in each cylinder) to each cylinder is corrected based upon a calculation result of the calculating means in such a way that the heat production in each cylinder becomes the same level with each other. In addition, Patent Document 2 and Patent Document 3 disclose a control apparatus for an internal combustion engine which determines a changing quantity of in-cylinder pressures between minute crank angles sampled by in-cylinder pressure detecting means as a heat generation rate and then, corrects a fuel supply quantity or an exhaust gas-recirculating quantity to an intake system based upon the determined heat generation rate during a high-load operational region. Further, Patent Document 4 discloses a method which controls ignition timing, an air-fuel ratio, an exhaust gas-rescirculating quantity and fuel injection timing by using a value obtained by subtracting a pressure integral value before a top dead center from a pressure integral value after a top dead center, each pressure integral value being calculated by integrating the in-cylinder pressures.
The above-mentioned conventional control apparatus for the internal combustion engine basically performs integral processing or differential processing of the in-cylinder pressures detected by the in-cylinder pressure detecting means for every minute crank angle. As a result, the calculating loads in the conventional control apparatus become remarkably large and therefore, it is practically difficult to apply the conventional control apparatus to an internal combustion engine for a vehicle, for example.
[Patent Document 1] Japanese Patent Application Laid-Open No. 63-268951
[Patent Document 2] Japanese Patent Application Laid-Open No. 4-81534
[Patent Document 3] Japanese Patent Application Laid-Open No. 4-81557
[Patent Document 4] Japanese Patent Application Laid-Open No. 2001-152952